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Excess Volumes of Mixing of Cl<sup>–</sup> and Br<sup>–</sup> with Na<sup>+</sup> and K<sup>+</sup> at 308.15 K in Aqueous Dioxane Mixed Solvent


BR Deshwal
KC Singh

Abstract

Excess volumes of mixing for six possible binary combinations of solutions of NaCl, KCl, NaBr and KBr have been determined at constant ionic strengths of 1.000 and 2.000 mol kg–1 at 308.15 K using a dilatometer in a water +1,4-dioxane mixed solvent system. Pitzer’s ion interaction model has been utilized to obtain binary and triplet interaction parameters, i.e. θV and ψV. The data were also analysed in the light of the Friedman model. Data are dependent on the nature of the common ion and do not support the cross square rule (CSR). The  deviation from the CSR increased with increasing ionic strength and is considered to arise from the appreciable contribution of triplet interactions and preferential solvation of the ions and ion-clusters in the mixed solvent system.

KEYWORDS: Excess volumes of mixing, Friedman model, Pitzer model, cross square rule.


Journal Identifiers


eISSN: 1996-840X
print ISSN: 0379-4350